Bucket elevator control systems



Sept. 23, 1958 o. LILLEHAUGEN BUCKET ELEVATOR CONTROL SYSTEMS Filed Nov. 25, 1955 15 INVENTOR lean 0. Ai/lelmuyen ATTORNEY United States Patent O BUCKET ELEVATOR CONTROL SYSTEMS Leon 0. Lillehaugen, St. Paul, Minn. Application November 25, 1955, Serial No. 549,029 12 Claims. ((31. 198-232) This invention relates to an improvement in bucket elevator control systems, and deals particularly with a system useful in preventing the overheating of elevator motors.

In elevators such as those used for elevating grain and other materials, difficulty is sometimes caused by the tendency for the material being lifted to fill the lift leg of the elevator housing and to stall the conveyor. The elevators are designed to pick up a predetermined amount of the material to be lifted and to convey this amount of material upwardly Within the confines of the housing. At the top of the lift leg, the material is carried over the top of the conveyor and discharged downwardly and outwardly into a suitable discharge spout or the like. When the grain or other material being lifted tends to pack together, the material being lifted will more than fill the 4 buckets and will substantially fill the lift leg housing.

If the material drops downwardly onto another bucket which is also overfilled, gradually sufficient grain will be found in the lift leg housing to stall the conveyor. This causes slippage of the conveyor on its pulleys and creates danger of fire. As materials such as grain are often extremely subject to fires, serious damage may result.

An object of the present invention resides in the provision of a control mechanism which obviates the difficulty due to packing the lift leg with the material being lifted. In general, this arrangement provides a means of relieving the pressure caused by the tendency for the lift leg to become packed and to guide certain of the material being lifted externally of the buckets to -a discharge gate. This discharge gate is designed to function due to the weight of the material thereupon to control the circuit to the elevator motor in a manner to stop operation of the elevator and also to stop' the supply of grain or other material being fed to the conveyors. The circuit to the motor remains open until the system has been manually reset.

A feature of the present invention lies in the provision of a control gate controlling the flow of a material into a bucket elevator and to control the position of this gate by an electric circuit or other suitable means. When excessive material is being forced into the lift leg of the conveyor, the supply into the elevator will be cut off. The bucket elevator will also cease operation until the operator determines and corrects the situation.

A further feature of the present invention resides in the provision of an alarm which is operated when the lift leg of the elevator contains excessive material. When the alarm is sounded, the operator is advised that the elevator is not in operation.

These and other objects and novel features of my invention will be more clearly and fully set forth in the following specification and claims.

In the drawing forming a part of this specification, the figure illustrates diagrammatically a bucket elevator having the control means forming a part thereof, intermediate portions of the elevator being broken away to simplify the illustration.

to the material on this next bucket.

The figure illustrates at A a bucket elevator having a lift leg housing 10 and a down leg housing 11 arranged in generally parallel relationship. The conveyor includes an endless belt 12 which is supported by a pulley 13 at the top of the elevator legs and a similar pulley 14 at the bottom of the elevator legs. The endless member or members 12 support buckets 15 of any suitable type designed to accommodate a supply of material to be elevated.

As is indicated in the figure, the top of the elevator is provided with an outlet 16 connected to any suitable conduit or connections. The lower end of the elevator housing includes a hopper or inlet 17 into which the supply of material to be elevated is inserted to direct the same into the bucket elevator.

Intermediate the upper and lower ends of the lift leg 10 of the elevator I provide an enlargement in the housing which may be integral with the housing or may be attached thereto to register with an opening such as 19 in the outer side of the housing 10. The remainder of the lift leg housing encloses the buckets 15 relatively closely.

When the bottom of the elevator is filled with grain or other such material, and when there is some tendency for this material to pack or cling together, each bucket tends to be overfilled, and in many instances projects laterally beyond the edges of the buckets. The projecting material often drops onto the next lower bucket, adding Continued operation of the elevator gradually tends to cause the grain to pack into the lift leg 10 to such an extent that the elevator motor becomes stalled or overloaded due to the force required to operate the conveyor.

The attachment to the lift leg 10 includes an upwardly and outwardly inclined baffle 20 which in effect forms a portion of the outer wall surface. A second baffie 21 inclines downwardly and outwardly from a point well above the upper extremity 22 of the baffle 20. This baflle 21 extends outwardly to enclose the upper edge 22 of the baffle 20 and terminates with its lower edge 23 below the level of the upper edge 22 of the bafile 20. Side Walls, one of which is indicated at 24, enclose the sides of the baffles, and in effect form extensions or projections from the sides of the rectangular leg housing 10.

When the elevator is operated and the lift leg 10 tends to become clogged with grain or the like, this material is gradually carried by movement of the bucket elevator into the enlargement form by the upwardly and outwardly inclined baiile 20. This tends to relieve the pressure on the elevator to some extent, and in many instances a temporary crowding of the lift leg will gradually correct itself if the conditions do not remain the same. However,

if the packing action continues, grain is eventually carried over the top 22 of the baffle 20 and falls upon a closure plate 25 which is pivotally supported at 26 between the side members 24.

. The control system is only diagrammatically shown in the drawings, as the specific construction of many of the details is unimportant. The elevator is shown as including an electric motor 27 which drives a belt or chain 29 connecting the motor pulley or sprocket 30 with a cooperable pulley or sprocket 31 on the-shaft 32 supporting the upper conveyor pulley or sprocket structure 13. The motor 27 thus acts to drive the bucket elevator to lift the material and dump it into the outlet 16.

The motor 27 is energized by line wires 33 and 34 which lead to a suitable current supply. A control switch 35 is interposed in one or both of the lines by means of which the operation of the elevator may be manually controlled. 'The line 33 leads through a conductor 36 to one terminal of the motor 37. The other motor terminal extends through a conductor 37 and a relay armature 39, which is connected by a conductor 40 to the line wire 34. The relay armature 39 is normally closed.

For the purpose of illustration, an arm-41 is shown attached to the closure 25 to pivot in .unison therewith, and a spring 42 is shown anchored to suitable fixed means and'tends to hold the closure in closed position. The arm 41 is engageable with one contact 43 of a pair of contacts 43, 44, the contacts thus operate in unison when the arm 41 is pivoted upwardly and accordingly are actuated when the closure 25 swings toward open position.

The switchcontacts 43, 44 control a circuit extending from line wire 33 through conductors 45 and 46 to the switch blade 43. The contact blade 44 is connected by a conductor 47 to one terminal of a relay coil 49, the other terminal of which is connected by conductors 50 and'51 to the line wire 34. Thus when a circuit is closed between the contact blades 43 and 44, the relay coil 49 is energized, thus acting upon the armature 39 to break the circuit to the motor 27' and to make a circuit from line wire 34 and conductor 40 through armature 39, contact 52 and conductor 53 to an alarm bell or other alarm 54. The other terminal of the alarm 54 is connected by a conductor 55 including a manually operable switch 56 to conductor 45 leading to the line wire 33.

A normally released solenoid latch 57 is connected by conductors 59 and 60 in parallel with the motor 27. Thus the solenoid latch is actuated simultaneously with the motor 27 and is urged into projected or latching position. A gate 61 is provided to control the passage from the hopper 17 into the lift leg of the bucket elevator. A bell crank 62 is pivoted at 63 and includes an arm 64 engageable with the slideable latch bolt 65 of the solenoid latch 57. The other arm 66 of the bell crank lever is connected by a chain or other flexible member 67 to the gate 61 to hold the gate in open position when the latch 57 is energized. This arrangement is provided so that the gate 61 can only be held in open position when the elevator motor 27 is in operation.

A lug or projection 69 is provided on the gate 61 capable of closing a pair of normally spaced contact blades 70, 71 when the gate 61 is lowered. A circuit is provided from line wire 33 through conductors 45 and 72 to the contact blade 71. The other blade is connected by a conductor 73 to a relay coil 74, the other terminal of which is connected by conductors 75 and 51 to the line wire 34. Thus when the switch contacts 70, 71 are closed, a circuit is provided to energize the relay coil 74.

A conveyor system indicated generally by the conveyor belt 76 is operated by a pulley 77 connected by a belt 79 to a motor 80. One terminal of the motor 80 is connected by conductors 81 and 45 to the line wire 33. The other motor terminal is connected by conductor 82 to the relay armature 83, the switch terminal 84 of which is connected by conductor 51 to the line wire 34. Thus when the contacts 70, 71 are closed, the relay armature 83 is moved in a manner to break the circuit to the conveyor motor or motors 80.

A light weight lid 85 is hinged at 86 to the front of the lift leg 10, this lid raising by gravity against the upper edge of the inclined bafile 20. The purpose of this lid is to prevent stray kernals of grain, carried upwardly by the conveyor, from being thrown into the outlet to rest upon the closure 25. As the bucket elevator travels at a substantial speed, some of the kernels of grain spill from the buckets and the upward force of movement is sufficient so that occasionally kernals might be thrown into the outlet provided except for this lid 85. The lid is sufficiently light so that it will be swung out of the path of grain when any substantial amount of grain is forced against the baffie 20.

The. operation of the apparatus is believed obvious from the foregoing description. When the elevator is placed into operation, the motor switch 35 is closed, closing the circuit to start the elevator motor and also closing the circuit to the solenoid latch 57. The gate 61 is manually opened and held in open position by the latch 57. Raising of the gate 61 opens the circuit to the relay 74, thereby permitting the relay to close the circuit to the conveyor motor 80.

In the event the lift leg of the elevator becomes packed with grain due to excessive grain being carried upwardly in the lift leg, this grain will be forced along the inclined baffle 20, raise the lid 85 and fall onto the closure 25. The weight of this grain will cause the closure to pivot downwardly, closing the circuit to the switch blades 43, 44 and operating the relay coil 49 to open the motor circuit. The circuit to the solenoid latch 57 is also broken so that the latch bolt 65 will retract and permit the gate 61 to drop. The dropping of the gate 61 will close the, circuit to the relay coil 75, thus breaking the circuit tothe. motor 80. Thus it will be seen that in the event the lift leg of the elevator becomes clogged with grain, the conveyor motor will be stopped, the supply of grain from the hopper will be cut off and the conveyor system supplying grain to the hopper will be stopped. Furthermore, a circuit will be closed to the alarm 54, providing an audible or visible indication that the elevator is not in operation. Theswitch 56 permits the signal to be turned off after the warning has been given.

After the main swtch 35 has been opened, the gate 61 may be opened to permit the lift leg to be cleared of grain and the grain can be removed from the closure 25. During this operation the gate 61 may be held up manually or the bottom of the elevator may be opened to permit the grain to be removed. After the main switch is closed, the motor 27 may be operated to clear the lift leg of grain. When, operating properly the gate 61 may be raised and additional grain may flow from the hopper into the elevator.- Simultaneously the conveyor system may operate to deliver additional grain to the hopper.

In accordance with the patent statutes, I have described the principles of construction and operation of my improvement in bucket elevator control systems, and while I have endeavored to set forth the best embodiment thereof, I desire to have it understood that obvious changes may be made within the scope of the following claims without departing from the spirit of my invention.

I claim:

1. A bucket elevator including an endless conveyor having buckets thereupon, means movably supporting said conveyor for movement through a pair of elevator legs, one of which comprises the lift leg, a pressure decreasing area in said lift leg comprising an upwardly and outwardly tapering enlargement in said lift leg, means forming a discharge opening associated with said enlargement for accommodating material in said lift leg which has been carried upwardly in said enlargement, means for operating said conveyor, and means responsive to the presence of material in said discharge opening for halting operation of said conveyor operating means.

2. The structure described in claim 1 and in which said elevator operating means is electrically operated by a circuit including a power supply.

3. The structure described in claim 2 and in which the means sensitive to the presence of material in said discharge includes a switch and including means controlled by said switch for halting operation of said elevator operating means.

4. A safety device for bucket elevators, including an endless conveyor having buckets thereon and a lift leg through which said buckets may pass, the device including a tapered enlargement in said lift leg into which excessive material carried upwardly by said buckets may be forced, means forming a discharge connected to said enlargement to receive material passing substantially through said enlargement, means for operating said elevator, said means being electrically actuated by a circuit for breaking the same, and means responsive to the presence of material in said discharge for actuating said circuit breaking means.

5. The construction described in claim 4 and including an inlet to said elevator, means for closing said inlet, and means actuated by said means responsive to the presence of material in said discharge for actuating said means for closing said inlet.

6. A safety device for bucket elevators including in combination an endless conveyor including a series of spaced buckets, a lift leg through which said buckets are movably supported, electrically operated means for actuating said conveyor, said lift leg having means forming a discharge passage connected thereto intermediate its ends into which material moved upwardly by said buckets but not enclosed therein may pass, means in the path of material in said discharge, a circuit to said electrically operated means, including a source of power and a circuit breaking means and means controlled by said means responsive to the presence of material in said discharge for actuating said circuit breaking means.

7. The structure described in claim 6, and including an inlet to said lift leg, closure means for closing said inlet, and means controlling the closing of said closure, and means actuated by said means responsive to the presence of material in said discharge for actuating said means controlling the closing of said closure.

8. The construction described in claim 6 and including alarm means actuated in unison with said circuit breaking means.

9. A safety device for a bucket elevator, including in combination an endless conveyor having a series of buckets thereon, a lift leg through which said buckets are movably supported, means forming an inlet to and means forming an outlet from said lift leg, a closure supported in said inlet for closing the same, electrically operated means for operating said conveyor, a circuit including a source of power supply and a circuit breaking means for said electically operated means, said lift leg having means forming a discharge connected thereto through which material forced upwardly in said lift leg but not included in said buckets may flow, means sensitive to material in said discharge for actuating said circuit breaking means, door closing means, means connecting said door closing means and said means responsive to the presence of said material in said discharge for actuating said door closing means simultaneously with the operation of said circuit breaking means.

10. The structure described in claim 9 and including alarm means connected to said means responsive to the presence of material in said discharge for producing an alarm simultaneously with the actuation of said circuit breaking means.

11. The structure described in claim 9 and including a conveyor arranged adjacent to said inlet to said lift leg and arranged to deliver material to said inlet, electrically operated means for actuating said conveyor, circuit to said means for actuating said conveyor including a power supply, and means in said last named circuit operated by the closing of said closure for opening this circuit.

12. A bucket elevator including an endless conveyor having a series of buckets thereon, a housing forming a lift leg through which said buckets move in an upward direction, said housing having an inlet opening adjacent its bottom end, an outlet opening adjacent its upper end and an auxiliary opening intermediate said inlet and outlet openings, casing means communicating with said auxiliary opening comprising a baffle diverging outwardly from the lower edge of said auxiliary opening and a pivotally mounted closure plate extending laterally from said bafile, and warning means actuated by said closure plate when a predetermined quantity of material has passed from said lifting leg over said bafile onto said closure plate.

References Cited in the file of this patent UNITED STATES PATENTS Germany June 20, 1936 

